Current-limiting device.



M. G. DIAZ & A. AZA'ROLA Y GRESILLQN. CURRENT LIMI'IIING DEVICE. APPLICATION FILED AUG. z2, 190e.

@Zz/zaga @gram ing Mr/wy sent-s MANUEL GARCIA-DIAZ AND ANTONIO AZROLA Y GRESILLQI GF'MADRID, SPAIN.

CURRENT-LIMITING DEVICE.'

, Specification of Letters Patent.

Application filed August 22, 1908. Serial No. 449,871.

T o alli whom ii may concern:

lie it known that. we, MANUEL (ii-inem mirnos. sulijeets ot the King of Spain, re.' dingr at Madrid, Spain, have invented neu' and uset`u|y Improvements in Current-Liiniting llei'iees, oi. which the following' is a specification.

The present invention has reference to an apparatus or instrument int-ended to prevent.. the the'l't of' electricity, and has par tieular reference to lnealis4 whereby the Cir cuit is broken and the lights thereof extinguished .for a certain length of time when a user `fraudulently attempts to introduce an extra laulp or otherwise-uses current bey-'ond the limit contracted for.

'llhe invention is shown in the aeeoinpanyim;r drawing. in u'hieh- Figure l represents diagrammatieally a simple embodiment ot the device and arri:utgenientv of circuits; Fig'. Q repreoue torni of the al'iparatus om' ploying, an auxiliary resistance; Fig. 3 represents another modified form employing` an auxiliary resistance; Fig. -lrepresents a forni of tho apparatus employing two sup- ]nlementa-iry resistanees; Fig'. represents an embodimentof the device employing` an insulating housing or casing' for the apparat.u.s;l` `ig. 5a a 'detailed' View ofthe-peiL tien of the structure represented in 'FigfY 5; l

closed airtight. ms'selrthe sides or lWalls of l the Walls of V consists of a flexible diaph ragni l) Iwl'liehcan'be distended hy the pressure :troni within. IR is an electric resistance of a' eertain yall-ie arranged in such a `form as to have substantially noself-induction. Surrounding the resistaneell and ifillingtheaes se] 4which contains the saine is a. gas of any suitable kind which maybe either air or vaporsl of any suitable liquid, or partly of liquid and partly eliges or por. This confined atmosphere may have a pressure equal to or greater' than 'atmospl'ieric 'pres sure, which pressure increases under the conditions hereinafter set forth. The dia phragm l -D is withl a lever P and the4 end of .this lever at the point C makes or breaks mechanically connecten electric Contact ivith apart fixed to the hase Z when the lever turns around its pivot. The lever l), and therefore the said diaphragm, has to act against the actioni oi a springr R, suitably attached toa portion of the fra-ine or base Z, in which spring; a' screw T titl-ns more orrless, its posit-ion `be-` ing determined by means vot an index i', and the said screw making contact with themend of lever P.

li the apparatus be arranged in series in a consun'iers circuit, which we will assume is to u'orl; at a rate ot 0.4 ainperes, the electric/current u'ill take its course from conductor 1 through terminal 2, resistance terminals 3, and al, on lever l), make-andhreak Contact C on insulated end of lever brztcket-, terminal (i, and the lamps iL, L1 to tht?y other conductor T. lf nonY the spring .l-if be suitably set by means of the. sereY T, the Contact C can `be kept fixed4 or closed noti:ithstanding the initial l'iez'itng or radiation iroru resistant-e R which dilates the and sets up pressure on the diaphragm. which will correspond to a? giyen equilibrium ot temperatures between the or dinary atmosphere and that of the apparatus and the latter will remain .in equilibrium. i I

It the fraudulent user introduces an'llextra lamp F, or one of a larger c-onsumnt ,nin pla ee of L or Ll, or takes extra energy other forni, the increase in theheat. t-l sistance Rdestroys the equilibrium 'which .is

'maintained by the spring Vand the circuit openedalmost instantaneously. The circuit being; thus broken, no caloritie energy is pro- Ia-tented Aug. 29,' 1911. l

duced by resistance R and the apparatus cools by radiation to the tei'uperat-ure of' the surrounding air and closes the circuitafresh, as the action of the Spring restablishes' the. Contact C. Thus as these phenomena recur successively, there is producedv an' inf,

terrupting action. y

Referring now particularly to Fiig. 2, a non-inductive auxiliary resistance RV eonneeted 'around 4 and. C, through 5 and (Vis arranged .in shunt between the two 'points of the. Contact C. Thisy resistance if fof a certain predetermined value and 4arranged in a' receptacle V1, Vmore oruless close to the vessel V, will answer two1 conditionnelle beine ,that et .ta'kingrp'f the Stmk. 0f nur `openings tob'e of longer duration 'by rendering the cooling of vessel- V more difficult.

If the vessel Vlbe brought into vgreater proximity to V, it will be possible to ermit. the transfer of heat from V1=to in such a way as to sustain the' dilation within the vessel V,y and .the oscillations gradually become slower or more deliberate so that the contact C will remai open, and the'circuit will have a great resistanceV solong as the userdoes not interrupt it, the apparatus which was improperly heated being thus caused to cool down. 'The' circuitconnections are hereinafter mentioned. Referringnow particularl to Fig. 3 a suitable auxiliary resistance R1 may be provided in shunt, with regard to the'main resistance and contact, between 2 and 6, through 2", 3 and 4 which resistance is placed in a chamber or compartment V nextto the main vessel or chamber V, the

. time.

-the period of rupture, since arrangement being such that the heat which is produced after the first opening of the circuit by. the action of the artitlon vWall, is transmitted from V1.to

ceaslng and that produced by R1 being taken up in an increasingquantity, Awhich is limited only by the radiation from the aparatus, thus roducing the effect of at first ightly and then indefinitely, fwhile current passes to the lamps Vit is insufiicientto cause them toflight up brightly but' sufiicient to support'the internal radiation thus restricting tthe fraud or theft. The user, having had the inconvenience of a variable or intermittent light which marks the fraud or theft he'has been committing, is obliged to leave the' apparatus to cool for a certain ngthening y s 'Referring to Fig. 4 plementary resistances R1 we rovide two sup- 2 one 'of which 'isinside the main vessel V and the other in a compartment V2 these resistances being in series with eachother and'so calculated and arranged that if fraud be committed, the rethe circuit lsupplements vthe diminished action of R, dilating the atmos here in the vessel V' in such are high. resistances, R

a way that te circuitv is the resistancesY R and R2 being connected through post 5 to post 4, said resistances being connected'to each other by wire 13 opened at once g -which 'connects post- 6 and 7, and resist- 4vessel V, acts an'ce R2 is connected at 8 to' wire 12. The

resistance R2 by its radiation of heat into as an additional compensat- ,infr influence against t'oo rapid radiation ofbheat from vvessel V.

The twodistinct-devces dSCl'b-d above by conductivity, the heat created by the resistance R.

-openin in the sup vring M, a'washer lc may be fitted to an impervious casing either in the air or underground or be let into a wall or a flooring.

Figs. 5 and 6 represent vertical diametrical sections of the device fitted for the purpose of being used,.within insulators A for heavy currents. drawings in their-natural dimensions, but can be made offany suitable size, according to the requirements to be fulfilled. They each cons1st`of a vessel or metallic recep. tacle V to the upper part of which an insulated conductor 1 runs which is lodged in a groove formed verticallyinside the circular wall of the insulator-` In the fguresall the heavy portions in black represent insulating washers or devices. From the terminal o the current reaches R and flows through the contact.holder late or perforated disk B,'infront of which is a yieldvThey are shown in the ing diaphra m or plate D suitably linsube appliedf'to the diaphragm by moving the micrometer s'c T. A .conducting wire 6 put in* or out of engagement with soldered to theiwas'her a passes through an port or base of the device and de ivers the current tov the user. entrance 'for this conductin made airtight and if a suita le washer and screw are fitted inthe base ofthe socket S, an airtight "chamber is created below the diaphra Air may be provided over and below t e dia hragm at the same initial ressur'e inv or' er to make the device absoutely independent of widely ranging external changes of pressure and temperature. The spring 'r rests on aninsulating lining k interposed between it and the base ofthe sockets `and the -whole arrangement described formsa single piece heldin .place The wire may be l in socket S by a thickscrew threaded fixing f below it, and an interposed insulating ring Jcz. l The metal socket or holder S is insulated from all the metaI- lic pieces with the exception'of the said ring M and its washer 7c and it may be screwe to a support and fixed where desired. In the upper outer surface of the vessel V are grooves G whereby through the medium of a suitable cement G2, the vessel can be fixed to the insulator A, and its other. or lower outer part is occupied by a Wide annular recess c into which is wound the calculated rcsistances R1 in Fig.

5 or 'R-2 in Fig. 6.v

The device represented in Fig. 6 does notdiier from that represented in Fig. exce t as regards the cross plate or disk B, which 1n Fig. 6 is insulated from V by ring k while 5 in Fig. 5 it. makes electrical contact with the The arrangement of the circuits is as fo1- lows :mReferring to fire-1st,Y interior radiation circuit through l, resistance R, 3, C2, D, and 6 correspondswith circuit 1, 2, 3, 4, C, 5, 6, in Fig. 1.,

The externall radiator circuit is through 3, B, V, 5', resistance R', and Wire 7', thus connecting the point 7 with (i. It corresponds to circuit 4, 5', 6'., v7 in Eig. 2. The apparatus being thus arranged, With the ex tcrnal radiation circuit near the vessel, at the expiration of a certain number of oscillations occasioned by the fraud, the light goes out and compels the user to take oif the Afraudulent lamps and to Wait till the device cools again.

If the external radiation circuit be removed' somewhat from the vessel V the oscillatiiig period increases with respect to the, previous condition, and if it be further removed its heating effect Will cease altogether, the resistance R then only serving to reduce the arcingf'or spark, although this is not really necessary. y

Referring to ,Fig` G the auxiliary resistance R', corresponding to the resistance -R o f Fig. 4, isintroduced into the vessel V, being connected to post `3 and to the resistance R2, the latter heilig situated exterior to the vessel V, and corresponding to vthe re sistanceR2 of Fig. 4. The resistance R2 is connected tof-Wire 9, which latter may be fcoiinccted to wireV 6. Except as to the niemhcr Il. thc structure of the device is 0therwisc the same as in Fig. 5, and the resistauf-cs li, ltr' and 4'R2 have the same effect as i in Fig. 4.

lVc claim:h 4, 1. A current limiting device comprising a |'1` electric'cii'ciiit,an expansible vessel in-' 'eluded within said circuit, a resistance for heatinc heatin said vessel, an adjustable contact contro led b the expansion of said vessel and controlling said circuit, a shunt circuit containing an auxiliary resistance adapted to convey current when said contact 'is broken, and a vessel in close proximity to said expansible vessel containing said auxil-4 iary resistance adapted to be heated thereby, said second-named vessel bein of substantially the saine Width as said expansibley vessel.

2. A current limiting device, comprising ani electric circuit, an expansible vessel included Within said circuit, a resistance for said vessel, an adjustable contact controlled by the expansion of said vessel and controlling said circuit, a shunt circuit y containing two auxiliary resistancesadapt- 65 edto convey current when said contact is broken, one of the said auxiliary resistances being arran ed in said expansible vessel, and a vessel in c ose proximity to said expansible vessel containing the other ot said auxiliary resistances and adapted tobe heated thereby.'

3. A current limiting device, comprising an electric circuit, an expansible vessel included Within said circuit, a resistance' for heating said VVessel, an adjustablecontact 'controlled by the expansion of said vessel.

and controlling said circuit, a` shunt circuit contafning two 'auxiliary resistances adapted to convey current when said contact is broken, one of the said auxiliary resistances b eing arranged n said expansible vessel, and the other of said auxiliary resistances being located outside said cxpansible vessel and adapted to impart heat thereto. In testimony Whereor We have signed our names to this specification in the presence of two subscribing Witnesses. l

MANUEL GAR-UIA DIAZ.

ANTONIOAZROLA Y GRESILLON:

vWitnesses E. DE MORA, JACIN'ro HENARnJo. 

